You can test for falsy values by coalescing to boolean with !! and make this inline : console.log(!!myVar ? myVar.myProp : 'fallbackValue') īe very careful though with this "falsy test", for if your variable is 0, '', or NaN, then it is falsy as well, even though it is not null/undefined. We will introduce their behavior differences in more detail in the next few subsections. Note: Traditional function expressions and arrow functions have more differences than their syntax. Each step along the way is a valid arrow function. In some cases, like yours, when your variable is supposed to hold an object, you can simply use the fact that any object is truthy whereas null and undefined are falsy values : if (myVar) Description Let's decompose a traditional anonymous function down to the simplest arrow function step-by-step. (use = null to check only for nulls values, and = null to check for null and undefined) console.log(myVar = null ? myVar.myProp : 'fallBackValue') + Unary plus operator indicates positive value (numbers are positive without this, however) - Unary minus operator negates an expression ++ Increment operator increments a value by 1 - Decrement operator decrements a value by 1 Logical complement operator inverts the value of a boolean. You can test for null and return some dependent expression in a single line with the ternary operator ?:, as already given in other answers : (also sometimes called Elvis operator, when written ?:), at least yet, unfortunately. There is no "null-safe navigation operator" in Javascript (EcmaScript 5 or 6), like ?. I'll redirect to Gibolt's answer, which covers it well. This long-wished feature is now available in JavaScript! example?.First // undefinedĮxample?.First.Second // Uncaught TypeError: Cannot read property 'Second' of undefined If you do not check a case, the left-side property must exist. If you require the first truthy value, you can use ||. To ensure a default defined value, you can use ?. const example = ĭomElement?.parentElement?.children?.?.nextElementSibling Any failure will immediately short-circuit and return undefined. If a property exists, it proceeds to the next check, or returns the value. It is called the Optional Chaining Operator, supported by all modern browsers. Once you are done with comparison operators do have a look at logical operators.You can now directly use ?. As a next step do spend some quality time practicing the operators understand how they differ from each other and also try breaking them. In this tutorial, we covered the JavaScript not equal and the other comparison operators. NOTE: THESE TWO EXAMPLES ARE NOT EXACTLY EQUAL, AS SHORTHAND CHECK WILL PASS AS LONG AS. Greater than or equal to (>=) - Checks if the value is greater than or equal to the value on the right When doing if checks, assignment operators can sometimes be omitted.Greater than (>) - Checks if the value on the left is greater than the value on the right.Strict equal to (=) - Checks is two values are equal and of similar type.Equal to (=) - Check if two values are equal.Other Comparison Operators:Īpart from the JavaScript not equal and Strict inequality operators, we have a few other operators that solve different use cases. In the last case, we used the strict inequality operator and it returned true as the values were of different types. Do note that in the latter case even though we passed 10 as a string the operator was able to compare both the values. In the second and third cases, it returned a false cause the values are the same. In the first case, it returned true as the values were different. However, the “!=” or Strict inequality operator does not attempt to do so and returns false if the values are unequal or of different types.īoth these operators solve different purposes and hence I would recommend practicing them to facilitate further understanding.Ĭode and Explanation: console.log(5 != 10) This operator tries to compare values irrespective of whether they are of different types. The JavaScript not equal or inequality operator (!=) checks whether two values are not equal and returns a boolean value. This article is a good starting point for the same, however, we do emphasize more on the JavaScript not equal (!= & !=) operators. Given its vast usage, every developer should understand the functionality of each operator. Hence these operators are used in decision making or as conditional statements for loops. These operators return a boolean value (true or false) based on the condition. Comparison operators in programming languages are used to compare two values.
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